c. the reshuffling of alleles in sexual reproduction.
Explanation:
During gametogenesis, meiosis occurs in reproductive cells. As a result, haploid gametes are produced. During meiosis, a process called ‘crossing over’ occurs in the pachytene stage of prophase I of meiosis. During crossing the chromosome segments are exchanged between non-sister chromatids of homologous chromosomes. Exchange of chromosome segment creates a new combination of genes or genetic recombination and produces hybrids. Thus, genetic variation occurs in all sexually reproducing organisms due to crossing over.
